During chickhood, female chicks will grow their tail feathers and wing feathers at the same time while their comb will grow at a slower pace. Also during chickhood, males at the same age as females will have little or no tail feathers but will grow wing feathers and comb at the same time. During adult hood, females will be smaller, have shorter tails, will lay eggs, will have a smaller comb, and will not crow. They will usually be less colorful than the roosters. Unless you have a breed like white leghorns which have only one color. Then this method won't work. Their tails will also curve.